In the field of sedimentary research, ever increasing emphasis has been put on the investigations of carbonates and carbonate rocks during the past 30 years. It is thus quite natural that in Central Europe - where c1assical carbonate in vestigations have already been carried out 100 years ago - numerous scholars turned to the study of this sediment type. On the occasion of a visiting professorship of G. M. FRIEDMAN at the Labora torium fur Sedimentforschung, Heidelberg University, a seminar on "Recent Developments of Carbonate Sedimentology in Central Europe" was held in July 1967. 90 persons involved in carbonate investigations participated, and 35 lectures were held. The present volume contains 30 papers summarizing the different subjects of the seminar. Of course these contributions only represent a small part of the work actually performed in the field of carbonate research in Central Europe. We believe, however, that they give a general survey of the work and the working methods employed in the different sectors of carbonate investigations. One of the purposes of the present symposium is to acquaint the English speaking countries with our recent results which usually - due to the language barrier - are not accessible to them.

WOLFGANG E. KRUMBEIN In this section we deal with special aspects of the Gavish Sabkha, and in two contributions with the very similar environments of the Ras Muhammad Pool (Chap. 10) and the Solar Lake (Chap. 15). Comparisons are made, however, in the individual contributions to other evaporative systems. Much ofthe work was stimulated by our late friend Eli Gavish during his pro- ductive years of sedimentological studies along the shores of the Gulf of Elat. An- other stimulus was initiated by the agreement that the Solar Lake and the Gavish Sabkha were selected as model cases for a Project of the International Geological Correlation Program. Its subject is Early Organic Evolution and Mineral and En- ergy Resources. It is presently chaired by one of the chapter authors (M. Schid- lowski). A subproject, chaired by S. Golubic and W. E. Krumbein is entitled Fossil stromatolitic microbial ecosystems and their modern analog. Another sub- project chaired by G. Eglinton deals with the possibilities of finding marker mol- ecules in ancient oil-producing sedimentary environments by comparison with nonpolluted modern systems. Also, this group had chosen the Solar Lake and the Gavish Sabkha as case study systems. Organic geochemistry, metal deposit for- mation in the biosedimentary environment and the comparison of recent and an- cient productivity and sulfate reduction systems thus were the main purposes of the specialized studies undertaken in the Gavish Sabkha and the Solar Lake.